Mobile communication system

ABSTRACT

A mobile communication system which is capable of, when carrying out mobile communication using a shared channel, increasing in efficiency of transmission timing of the data transmission rate request value to prevent wasteful power consumption and hence reduce power consumption. The mobile station apparatus  102  of the mobile communication system measures CIR of the received signal from the base station apparatus  101  at the CIR measuring section  306 , and decides the data transmission rate request value corresponding to the measured CIR value at the rate request value deciding section  307 . Also, it detects an error of the received signal at the CRC section  304 , and, when no error is found, calculates a difference between the average data transmission rate from the base station apparatus  101  and the data transmission request value at the rate request value transmission controlling section  308 . Then, it transmits the data transmission rate request value to the base station apparatus  101  only when the obtained difference is larger than a threshold value.

TECHNICAL FIELD

The present invention relates to a mobile communication system, and to abase station apparatus and a mobile station apparatus constituting thesame.

BACKGROUND ART

As one of the standards for the mobile communication system, there is astandard called cdma2000. To cdma2000 is applied HDR (High Data Rate)which uses a dedicated frequency band for data communication in additionto a dedicated frequency band for voice communication. In HDR, a sharedchannel in which the dedicated frequency band (channel) for datacommunication is shared by a plurality of users is used.

The shared channel is defined as a channel in which data transmissionrate (hereinafter, simply referred to as “rate”) is appropriatelychangeable, and the same frequency is used by a plurality of mobilestation apparatuses wherein only one mobile station apparatus that hasbeen selected by a base station apparatus is permitted to useexclusively the frequency in time-sharing mode to carry out datacommunication.

In a conventional mobile communication system, which uses such sharedchannel as described above, first, a plurality of mobile stationapparatuses receive a pilot burst signal transmitted from a base stationapparatus. Then, each mobile station apparatus measures CIR (Carrier toInterference Ratio), which represents the reception quality, based onthe received pilot burst signal, and transmits a rate request valueaccording to the CIR measurement value to the base station apparatus. Atthis time, transmission of the rate request value is carried out fromevery mobile station apparatus within the communication area at the sametiming. Then, the base station apparatus, on receiving the rate requestvalue from each mobile station apparatus, selects a mobile stationapparatus to which data is to be transmitted based on the received raterequest values, and transmits the data to the relevant mobile stationapparatus at a rate of the rate request value received from the selectedmobile station apparatus.

However, in the conventional system, since the data is transmitted onlyto the mobile station apparatus that has been selected by the basestation apparatus, the mobile station apparatus, even when it transmitsthe rate request value, can not receive the data unless it is selectedby the base station apparatus, and thus needs to transmit the raterequest value continuously until it is selected by the base stationapparatus.

That is to say, when the rate request value transmitted from the mobilestation apparatus is smaller than a rate assigned to the datatransmission by the base station apparatus, the relevant mobile stationapparatus is rarely selected but nevertheless needs to transmit the raterequest value continuously, thus resulting in a problem of uselesselectric power consumption for that continuous period of time. Since thepower consumption for the transmission in the mobile station apparatusis large, a battery runs out earlier due to useless power consumption.

Further, when the mobile station apparatus is in a standstill or movingat a low speed, the mobile station apparatus transmits every time thesame rate request value, even though CIR fluctuates little. Therefore,in this case also, there is such a problem of useless electric powerconsumption.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a mobilecommunication system that is capable of, when carrying out mobilecommunication using a shared channel, increasing in efficiency oftransmission timing of the data transmission rate request value toprevent wasteful power consumption and hence reduce power consumption.

According to an aspect of the invention, a mobile communication systemcomprises a mobile station apparatus that transmits data transmissionrate request value, and a base station apparatus that selects the mobilestation apparatus to which data is transmitted based on the datatransmission rate request value received from the mobile stationapparatus and transmits data to the selected mobile station apparatus atthe data transmission rate request value received from the selectedmobile station apparatus, wherein the mobile station apparatus comprisesfirst receiving means for receiving an average data transmission ratetransmitted from the base station apparatus, measuring means formeasuring quality of the received signal from the base stationapparatus, deciding means for deciding the data transmission raterequest value based on the reception quality measured by the measuringmeans, first calculating means for calculating a difference between thedata transmission rate request value decided by the deciding means andthe average data transmission rate received by the first receivingmeans, judging means for judging whether or not the result ofcalculation by the first calculating means is equal to or larger than areference value, and first controlling means for making the datatransmission rate request value decided by the deciding means betransmitted to the base station apparatus when it is judged by thejudging means that the result of calculation by the first calculatingmeans is equal to or larger than the reference value, and wherein thebase station apparatus comprises second receiving means for receivingthe data transmission rate request value transmitted from the mobilestation apparatus, selecting means for selecting the mobile stationapparatus to which data is transmitted based on the data transmissionrate request value received by the second receiving means, secondcalculating means for calculating an average of a data transmission ratefor transmitting data to the mobile station apparatus selected by theselecting means as the average data transmission rate, and secondcontrolling means for making the average data transmission ratecalculated by the second calculating means be transmitted to the mobilestation apparatus.

According to another aspect of the invention, a mobile communicationsystem comprising a mobile station apparatus that transmits datatransmission rate request value, and a base station apparatus thatselects the mobile station apparatus to which data is transmitted basedon the data transmission rate request value received from the mobilestation apparatus and transmits data to the selected mobile stationapparatus at the data transmission rate request value received from theselected mobile station apparatus, wherein the mobile station apparatuscomprises first measuring means for measuring quality of the receivedsignal from the base station apparatus, deciding means for deciding thedata transmission rate request value based on the reception qualitymeasured by the first measuring means, first storing means for storingthe data transmission rate request value decided by the deciding means,first judging means for comparing the previous data transmission raterequest value stored in the first storing means and the latest datatransmission rate request value, and judging whether or not both thereofare different from each other, and controlling means for making thelatest data transmission rate request value be transmitted to the basestation apparatus when it is judged by the first judging means that theprevious data transmission rate request value and the latest datatransmission rate request value are different from each other, andwherein the base station apparatus comprises second measuring means formeasuring quality of the received signal from the mobile stationapparatus, receiving means for receiving the data transmission raterequest value transmitted from the mobile station apparatus, secondstoring means for storing the data transmission rate request valuereceived by the receiving means by relating it to the mobile stationapparatus, second judging means for judging, when there is any mobilestation apparatus the data transmission rate request value of which hasnot been received this time by the receiving means, as for the relevantmobile station apparatus, whether or not the reception quality measuredby the second measuring means is equal to or larger than a referencevalue, and control means for using, when it is judged by the secondjudging means that the measured value of the reception quality is equalto or larger than the reference value, as for the relevant mobilestation apparatus, the previous data transmission rate request valuestored in the second storing means as the data transmission rate requestvalue to be used for selecting the mobile station apparatus to whichdata is transmitted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a constitution of a mobilecommunication system according to a first embodiment of the presentinvention;

FIG. 2 is a block diagram illustrating a constitution of a base stationapparatus in the mobile communication system according to the firstembodiment of the present invention;

FIG. 3 is a block diagram illustrating a constitution of a mobilestation apparatus in the mobile communication system according to thefirst embodiment of the present invention;

FIG. 4 is a block diagram illustrating a constitution of a base stationapparatus in a mobile communication system according to a secondembodiment of the present invention;

FIG. 5 is a block diagram illustrating a constitution of a mobilestation apparatus in the mobile communication system according to thesecond embodiment of the present invention;

FIG. 6 is a diagram used for illustrating transmission timing of therate request value in the mobile station apparatus of the mobilecommunication system according to the second embodiment of the presentinvention; and

FIG. 7 is a diagram used for illustrating transmission timing of therate request value in a mobile station apparatus of a mobilecommunication system according to a third embodiment of the presentinvention.

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below in detailwith reference to accompanying drawings.

(First Embodiment)

FIG. 1 is a block diagram illustrating a constitution of a mobilecommunication system according to a first embodiment of the presentinvention.

This mobile communication system includes, as shown in FIG. 1, a basestation apparatus 101 and a plurality of mobile station apparatuses 102.The base station apparatus 101 and the mobile station apparatus 102carry out radio communication using a shared channel in HDR applied tocdma2000.

The base station apparatus 101 includes, as shown in FIG. 2, an antenna201 for transmitting/receiving common use, an RF (Radio Frequency)section 202, a multiplexing section 203, four modulating/spreadingsections 204, 205, 206 and 207, a despreading/demodulating section 208,a dedicated channel coding section 209, a MAC (Medium Access Control)channel assembling section 210, a TPC (Transmit Power Control)generating section 211, a radio resource controlling section 212, anaverage rate calculating section 214, a broadcast channel assemblingsection 215 and a buffering section 216.

The mobile station apparatus 102 includes, as shown in FIG. 3, anantenna 301 for transmitting/receiving common use, an RF section 302, adespreading/demodulating section 303, a CRC (Cycle Redundancy Check)section 304, a disassembling section 305, a CIR (Carrier to InterferenceRatio) measuring section 306, a rate request value deciding section 307,a rate request value transmission controlling section 308, amultiplexing section 309 and a modulating/spreading section 310.

Next, the operation of the mobile communication system having theconstitution as described above will be described.

First, the base station apparatus 101 modulates and spreads a pilotburst signal in the modulating/spreading section 204.

Then, the modulated and spread pilot burst signal is multiplexed withother various signals that have been modulated and spread (for example,an average rate signal assigned to the shared channel, which will bedescribed later, etc.) in the multiplexing section 203, subjected topredetermined transmission processing such as up-conversion etc. in theRF section 202, and then transmitted as a radio signal via antenna 201.

After that, the mobile station apparatus 102 receives via antenna 301the signal transmitted as a radio signal from the base station apparatus101. The signal received by antenna 301 is subjected to predeterminedreception processing such as down-conversion etc. in the RF section 302,and outputted to the despreading/demodulating section 303.

Then, the received signal inputted from the RF section 302 is despreadand demodulated in the despreading/demodulating section 303, andoutputted to the CRC section 304 and the CIR measuring section 306.

Then, CIR of the pilot burst signal included in the despread anddemodulated received signal is measured in the CIR measuring section306. The measured CIR value is outputted to the rate request valuedeciding section 307.

Then, in the rate request value deciding section 307, a ratecorresponding to the measured CIR value is selected from the previouslystored data transmission rates, and outputted to the rate request valuetransmission controlling section 308 as the mobile station's own raterequest value.

On the other hand, CRC check on the received signal which has beendespread and demodulated is performed in the CRC section 304, and, as aresult of the CRC check, when no error is detected, the received signalis outputted to the disassembling section 305. When error is detected,the received signal is not outputted to the disassembling section 305.

Then, in the disassembling section 305, on receiving the despread anddemodulated received signal from the CRC section 304, the receivedsignal is disassembled to pick out the average rate signal broadcastedby the base station apparatus 101. The average rate signal thus obtainedis outputted to the rate request value transmission controlling section308.

Then, in the rate request value transmission controlling section 308,the difference between the own rate request value decided in the raterequest value deciding section 307 and the average rate signalbroadcasted by the base station apparatus 101 is obtained, and only whenthe obtained difference is larger than the previously set thresholdvalue (reference value), the rate request value is outputted to themultiplexing section 309. That is to say, when the difference betweenthe rate request value and the average rate is not more than thethreshold value, the rate request value is not outputted to themultiplexing section 309 (that is, it is not transmitted to the basestation apparatus 101).

Then, the rate request value inputted to the multiplexing section 309 ismultiplexed with its own transmission signal (for example, a pilotsymbol signal for controlling the transmit power, etc.) in themultiplexing section 309. This multiplexed signal is modulated andspread in the modulating/spreading section 301, subjected to thepredetermined transmission processing such as up-conversion etc., andthen transmitted as a radio signal via antenna 301.

After that, the base station apparatus 101 receives via antenna 201 thesignal transmitted as a radio signal from the mobile station apparatus102. The signal received via antenna 201 is subjected to thepredetermined reception processing such as down-conversion etc. in theRF section 202, and outputted to the despreading/demodulating section208.

Then, the received signal inputted from the RF section 202 is despreadand demodulated in the despreading/demodulating section 208, andoutputted to the TPC generating section 211 and the radio resourcecontrolling section 212.

Then, a TPC signal for controlling transmit power of the mobile stationapparatus 102 is generated according to the pilot symbol signal includedin the despread and demodulated received signal in the TPC generatingsection 211. The generated TPC signal is assembled into a MAC channel inthe MAC channel assembling section 210, modulated and spread in themodulating/spreading section 206, and outputted to the multiplexingsection 203.

On the other hand, the mobile station apparatus 102 to which the data istransmitted is selected in the radio resource controlling section 212based on the rate request value included in the received signal that hasbeen despread and demodulated. Specifically, for example, the raterequest values from the respective mobile station apparatuses 102 arecompared, and the mobile station apparatus 102 that has the largest raterequest value is selected. This selection result is outputted to thebuffering section 216 and the dedicated channel coding section 209. Inaddition, the radio resource controlling section 212 outputs a signalthat specifies the modulating mode (for example, QPSK, 16QAM, 64QAM,etc.) to the modulating/spreading section 205.

Furthermore, the criterion of selecting the mobile station apparatus 102is not limited to the example described above. For example, in order toallow every mobile station apparatus 102 to carry out communication,such selection may be adopted that the mobile station apparatus 102which has a small rate request value is selected. However, in this case,the average data transmission rate (throughput) of the base stationapparatus 101 is decreased.

Then, in the buffering section 216, the transmission data for theselected mobile station apparatus 102 is read out. To the read outtransmission data is given destination information for the relevantmobile station apparatus 102 in the dedicated channel coding section209. The data to which the destination information is given is modulatedin accordance with the specified modulating mode and spread in themodulating/spreading section 205, and then outputted to the multiplexingsection 203.

Moreover, the radio resource controlling section 212 outputs informationon the rate that has been used for data transmission to the selectedmobile station apparatus 102 sequentially to the average ratecalculating section 214.

Then, the average value (average rate) of the rates that have been usedfor data transmission to the selected mobile station apparatus 102 iscalculated in the average rate calculating section 214. The average ratesignal is assembled as broadcast channel information in the broadcastchannel assembling section 215, modulated and spread in themodulating/spreading section 207, and then outputted to the multiplexingsection 203.

The respective signals described above and outputted to the multiplexingsection 203 (TPC signal, transmission data with destination information,average rate signal and pilot burst signal) are multiplexed in themultiplexing section 203, subjected to the predetermined transmissionprocessing such as up-conversion etc. in the RF section 202, and thentransmitted as a radio signal via antenna 201.

After that, the mobile station apparatus 102 receives the signal fromthe base station apparatus 101, and when its own destination informationis included in that received signal, receives the succeedingtransmission data.

Therefore, according to the mobile communication system of thisembodiment, since the mobile station apparatus 102 transmits the raterequest value to the base station 101 only when no error exists in thereceived signal and when the difference between the rate request valueand the average rate is larger than a threshold value, it is notnecessary to transmit the rate request value all the time like theconventional art, and it is possible to increase in efficiency oftransmission timing of the data transmission rate request value toprevent wasteful power consumption and hence reduce power consumption ina mobile communication using a shared channel.

(Second Embodiment)

FIG. 4 is a block diagram illustrating a constitution of a base stationapparatus in a mobile communication system according to a secondembodiment of the present invention, FIG. 5 is a block diagramillustrating a constitution of a mobile station apparatus in the mobilecommunication system according to the second embodiment. The basestation apparatus and the mobile station apparatus of the mobilecommunication system have the same basic structure as the base stationapparatus and the mobile station apparatus in the first embodiment shownin FIG. 2 and FIG. 3 respectively, so that the identical componentelements are given with the same reference numeral and their descriptionwill be omitted.

The base station apparatus 401 shown in FIG. 4 includes, in addition tothe antenna 201, the RF section 202, the multiplexing section 203, thethree modulating/spreading section 204, 205 and 206, thedespreading/demodulating section 208, the dedicated channel codingsection 209, the MAC channel assembling section 210, the TPC generatingsection 211 and the buffering section 216 as described above, a radioresource controlling section 402 and a SIR (Signal to InterferenceRatio; the ratio of desired signal power to interference signal power)measuring section 403 which are essential elements of this embodiment.

The mobile station apparatus 501 shown in FIG. 5 includes, in additionto the antenna 301, the RF section 302, the despreading/demodulatingsection 303, the CRC section 304, the CIR measuring section 306, therate request value deciding section 307, the multiplexing section 309and the modulating/spreading section 310 as described above, a raterequest value transmission controlling section 502 which is an essentialelement of this embodiment.

Next, the operation of the mobile communication system having theconstitution as described above will be described. As for the parts thatare the same as those in the first embodiment, the description thereofwill be omitted or just briefly described.

First, the base station apparatus 401 multiplexes the pilot burst signalthat has been modulated and spread with other signals that have beenmodulated and spread, and transmits the multiplexed signals as a radiosignal.

After that, the mobile station apparatus 501, on receiving the signaltransmitted from the base station apparatus 401, measures CIR of thepilot burst signal in the CIR measuring section 306, decides a raterequest value corresponding to the measured CIR value in the raterequest value deciding section 307 and outputs the decided rate requestvalue to the rate request value transmission controlling section 502.The rate request value transmission controlling section 502 has afunction of storing the rate request value.

Then, the rate request value transmission controlling section 502,utilizing the function of storing the rate request value, compares thepresent rate request value from the rate request value deciding section307 with the previous rate request value, and only when the present raterequest value is different from the previous rate request value, outputsthe present rate request value to the multiplexing section 309. That isto say, when the present rate request value is the same as the previousrate request value, the present rate request value is not outputted tothe multiplexing section 309 (that is, it is not transmitted to the basestation apparatus 401).

Then, the multiplexing section 309 multiplexes, when the rate requestvalue is inputted from the rate request value transmission controllingsection 502, the input rate request value with its own transmissionsignal which includes the pilot symbol signal for controlling thetransmit power, and then transmits the multiplexed signals as a radiosignal. On the contrary, when the rate request value is not inputted,only the pilot symbol signal for controlling transmission power istransmitted as a radio signal.

After that, the base station apparatus 401 receives the signaltransmitted as a radio signal from the mobile station apparatus 501,processes the received signal in the despreading/demodulating section208, and then outputs the processed received signal to the TPCgenerating section 211, the radio resource controlling section 402 andthe SIR measuring section 403.

Then, when the rate request value is included in the received signal,similar to the radio resource controlling section 212 in the firstembodiment, the radio resource controlling section 402 selects themobile station apparatus 102 to which the data is transmitted based onthe rate request value. Specifically, for example, the rate requestvalues from the respective mobile station apparatus 102 are compared andthe mobile station apparatus 102 that has the largest rate request valueis selected. Then, the transmission data for the selected mobile stationapparatus 501 is read out in the buffering section 216, and to this readout transmission data is given destination information for the relevantmobile station apparatus 501 in the dedicated channel coding section209.

On the contrary, when the rate request value is not included in thereceived signal, i.e., when the rate request value is not received butonly the pilot symbol signal is received, the radio resource controllingsection 402 inputs the measured SIR value of the received signal fromthe SIR measuring section 403, and decides whether or not the inputmeasured SIR value is equal to or larger than a preset threshold value(reference value), that is, whether or not the reception quality isequal to or higher than the preset quality. As a result, when themeasured SIR value is equal to or larger than the threshold value, theradio resource controlling section 402 decides that the mobile stationapparatus 501 did not transmit rate request value this time since itsvalue was the same as the previous rate request value, and, as for therelevant mobile station apparatus 501, performs the above-mentionedselection (selection of the mobile station apparatus 501 from which thedata is transmitted) using the rate request value that has beenpreviously received.

Therefore, according to the mobile communication system of thisembodiment, since the mobile station apparatus 501 transmits the latestrate request value to the base station 401 only when the latest raterequest value is different from the previous rate request value, and thebase station apparatus 401 selects the mobile station apparatus to whichthe date is transmitted using the rate request value previously receivedwhen the base station apparatus 401 dose not receive the rate requestvalue this time from the mobile station apparatus 501 and when themeasured SIR value of the received signal is equal to or larger than thethreshold value, it is not necessary for the mobile station apparatus totransmit the rate request value all the time like the conventional art,and it is possible to increase in efficiency of transmission timing ofthe data transmission rate request value to prevent wasteful powerconsumption and hence reduce power consumption in a mobile communicationusing a shared channel.

Further, since SIR value is used as a reception quality, the basestation apparatus 401 can measure correctly the quality of the receivedsignal, and perform the above-mentioned selection correctly.

(Third Embodiment)

A third embodiment is the case where the mobile station apparatustransmits the rate request value to the base station apparatus 401 evenif there is no change in the rate request value, when such a state hasbeen continued for a predetermined period of time that the mobilestation apparatus does not transmit the latest rate request value to thebase station apparatus 401 since the latest rate request value is thesame as the previous rate request value in the second embodiment.

FIG. 6 is a diagram used for illustrating transmission timing of therate request value in the mobile station apparatus 501 of the secondembodiment, wherein FIG. 6A shows an example of the rate request valuedecided by the mobile station apparatus 501, FIG. 6B shows an example ofthe rate request value transmitted from the mobile station apparatus501, and FIG. 6C shows an example of the rate request value recognizedby the base station apparatus 401 when an error has occurred.

In the second embodiment, as shown in FIG. 6B, the rate request value istransmitted only when the rate request value has changed. At this time,for example, when the rate request value (“4”) which corresponds to theframe F1 immediately before the rate request value becomes not to changeis transmitted from the mobile station apparatus 501 to the base stationapparatus 401, and when the rate request value is erroneously recognizedby the base station apparatus 401 (for example, “4”→“5”) as shown inFIG. 6C, then consequently the erroneous rate request value iscontinuously recognized by the base station apparatus 401 during theperiod D1 until the rate request value is transmitted again.Accordingly, the base station apparatus 401 selects the target to whichthe data is transmitted (mobile station apparatus 501) based on theerroneous rate request value until the rate request value changes nexttime, so that there is a possibility that the above-mentioned selectionmay not be made correctly during the period D1 where the rate requestvalue does not change.

So, in this embodiment, the mobile station apparatus (hereinafter, themobile station apparatus in this embodiment is given with a referencenumber “501 a”) transmits the rate request value to the base stationapparatus 401 even if there is no change in the rate request value, whensuch a state has been continued for a predetermined period of time thatthe mobile station apparatus does not transmit the rate request value.That is, even when there is no change in the rate request value, therate request value is retransmitted to the base station apparatus 401 ata predetermined period.

FIG. 7 is a diagram corresponding to FIG. 6 and used for illustratingtransmission timing of the rate request value in the mobile stationapparatus 501 a of this embodiment, wherein FIG. 7A shows an example ofthe rate request value decided by the mobile station apparatus 501 a,FIG. 7B shows an example of the rate request value transmitted by themobile station apparatus 501 a, and FIG. 7C shows an example of the raterequest value recognized by the base station apparatus 401 when an errorhas occurred.

In this embodiment, even in a period when the rate request value doesnot change, for example, as shown in FIG. 7B, in the case where such astate that the rate request value is not transmitted for four framessuccessively, the rate request value is bound to be transmitted at thefifth frame (in the example of FIG. 7, frame F6 and frame F11) even whenthere is no change in the rate request value. That is to say, the raterequest value is transmitted at a period of five frames. Accordingly, asshown in FIG. 7C, even when the rate request value corresponding to theframe immediately before the rate request value becomes not to change(in the example of FIG. 7, frame F1) is erroneously recognized by thebase station apparatus 401, the same rate request value is transmittedfrom the mobile station apparatus 501 a at a period of five frames, sothat the base station apparatus 401 is able to recognize the correctrate request value and to correct the error of the rate request valuepromptly as long as the above rate request value is received correctly.That is, the time (duration) when erroneous information is held isreduced from D1 to D2 (D1=D2+D3). Here, the durations D1 and D2 denotedurations when the base station apparatus 401 misrecognizes the raterequest value and the duration D3 denotes a duration when the basestation apparatus recognizes the rate request value correctly.

Therefore, according to the mobile communication system in thisembodiment, since the mobile station apparatus 501 a transmits(retransmits) the rate request value to the base station apparatus 401at a predetermined period even if there is no change in the rate requestvalue, when such a state has been continued for a predetermined periodof time that the mobile station apparatus 501 a does not transmit therate request value, the period of time when an erroneous rate requestvalue is held in the base station apparatus 401 can be reduced, and thebase station apparatus 401 can select promptly and correctly the targetto which the data is transmitted.

Further, although the period of retransmitting the rate request value isfive frames in this embodiment, it is not limited to this. The periodfor retransmission of the rate request value is changeable appropriatelydepending on the propagation conditions. For example, when thepropagation conditions change drastically, by reducing the period ofretransmission, and when the propagation conditions do not change sodrastically, by elongating the period of retransmission, respectively,the power consumption of the mobile station apparatus 501 a can bereduced and the above-mentioned selection in the base station apparatus401 can be carried out more correctly.

Furthermore, although the present invention is applicable, particularlyto the shared channel used in HDR which is applied to cdma2000, it isnot limited to this, for example, the same is also applicable to adesired adaptive modulation system in which a base station apparatustransmits data at a data transmission rate requested by a mobile stationapparatus.

This application is based on the Japanese Patent ApplicationNo.2000-232268 filed on Jun. 26, 2000, and the Japanese PatentApplication No.2000-204222 filed on Jul. 5, 2000, entire content ofwhich is expressly incorporated by reference herein.

Industrial Applicability

The invention is applicable to a mobile communication system, and a basestation apparatus and a mobile station apparatus constituting the same.

1. A mobile communication system comprising a mobile station apparatusthat transmits data transmission rate request value, and a base stationapparatus that selects the mobile station apparatus to which data istransmitted based on the data transmission rate request value receivedfrom the mobile station apparatus and transmits data to the selectedmobile station apparatus at the data transmission rate request valuereceived from the selected mobile station apparatus, wherein the mobilestation apparatus comprises: first receiving means for receiving anaverage data transmission rate transmitted from the base stationapparatus; measuring means for measuring quality of the received signalfrom the base station apparatus; deciding means for deciding the datatransmission rate request value based on the reception quality measuredby said measuring means; first calculating means for calculating adifference between the data transmission rate request value decided bysaid deciding means and the average data transmission rate received bysaid first receiving means; judging means for judging whether or not theresult of calculation by said first calculating means is equal to orlarger than a reference value; and first controlling means for makingthe data transmission rate request value decided by said deciding meansbe transmitted to the base station apparatus when it is judged by saidjudging means that the result of calculation by said first calculatingmeans is equal to or larger than the reference value, and wherein thebase station apparatus comprises: second receiving means for receivingthe data transmission rate request value transmitted from the mobilestation apparatus; selecting means for selecting the mobile stationapparatus to which data is transmitted based on the data transmissionrate request value received by said second receiving means; secondcalculating means for calculating an average of a data transmission ratefor transmitting data to the mobile station apparatus selected by saidselecting means as the average data transmission rate; and secondcontrolling means for making the average data transmission ratecalculated by said second calculating means be transmitted to the mobilestation apparatus.
 2. A communication method in a mobile communicationsystem comprising a mobile station apparatus that transmits datatransmission rate request value, and a base station apparatus thatselects the mobile station apparatus to which data is transmitted basedon the data transmission rate request value received from the mobilestation apparatus and transmits data to the selected mobile stationapparatus at the data transmission rate request value received from theselected mobile station apparatus, comprising: a first receiving step inwhich the mobile station apparatus receives an average data transmissionrate transmitted from the base station apparatus; a measuring step inwhich the mobile station apparatus measures quality of the receivedsignal from the base station apparatus; a deciding step in which themobile station apparatus decides the data transmission rate requestvalue based on the reception quality measured in said measuring step; afirst calculating step in which the mobile station apparatus calculatesa difference between the data transmission rate request value decided insaid deciding step and the average data transmission rate received insaid first receiving step; a judging step in which the mobile stationapparatus judges whether or not the result of calculation in said firstcalculating step is equal to or larger than a reference value; a firstcontrolling step in which the mobile station apparatus makes the datatransmission rate request value decided in said deciding step betransmitted to the base station apparatus when it is judged in saidjudging step that the result of calculation in said first calculatingstep is equal to or larger than the reference value; a second receivingstep in which the base station apparatus receives the data transmissionrate request value transmitted from the mobile station apparatus; aselecting step in which the base station apparatus selects the mobilestation apparatus to which data is transmitted based on the datatransmission rate request value received in said second receiving step;a second calculating step in which the base station apparatus calculatesan average of a data transmission rate for transmitting data to themobile station apparatus selected in said selecting step as the averagedata transmission rate; and a second controlling step in which the basestation apparatus makes the average data transmission rate calculated insaid second calculating step be transmitted to the mobile stationapparatus.
 3. A mobile station apparatus used in a mobile communicationsystem comprising the mobile station apparatus that transmits datatransmission rate request value, and a base station apparatus thatselects the mobile station apparatus to which data is transmitted basedon the data transmission rate request value received from the mobilestation apparatus and transmits data to the selected mobile stationapparatus at the data transmission rate request value received from theselected mobile station apparatus, comprising: first receiving means forreceiving an average data transmission rate transmitted from the basestation apparatus; measuring means for measuring quality of the receivedsignal from the base station apparatus; deciding means for deciding thedata transmission rate request value based on the reception qualitymeasured by said measuring means; first calculating means forcalculating a difference between the data transmission rate requestvalue decided by said deciding means and the average data transmissionrate received by said first receiving means; judging means for judgingwhether or not the result of calculation by said first calculating meansis equal to or larger than a reference value; and first controllingmeans for making the data transmission rate request value decided bysaid deciding means be transmitted to the base station apparatus when itis judged by said judging means that the result of calculation by saidfirst calculating means is equal to or larger than the reference value.4. The mobile station apparatus according to claim 3, further comprisingerror detecting means for detecting an error of the received signal fromthe base station apparatus, and wherein said first controlling meansmakes the data transmission rate request value decided by said decidingmeans be transmitted to the base station apparatus when it is determinedby said error detecting means that the received signal is errorless andwhen it is judged by said judging means that the result of calculationby said first calculating means is equal to or larger than the referencevalue.
 5. A method of controlling information transmission in a mobilestation apparatus used in a mobile communication system comprising themobile station apparatus that transmits data transmission rate requestvalue, and a base station apparatus that selects the mobile stationapparatus to which data is transmitted based on the data transmissionrate request value received from the mobile station apparatus andtransmits data to the selected mobile station apparatus at the datatransmission rate request value received from the selected mobilestation apparatus, comprising: a first receiving step of receiving anaverage data transmission rate transmitted from the base stationapparatus; a measuring step of measuring quality of the received signalfrom the base station apparatus; a deciding step of deciding the datatransmission rate request value based on the reception quality measuredin said measuring step; a first calculating step of calculating adifference between the data transmission rate request value decided insaid deciding step and the average data transmission rate received insaid first receiving step; a judging step of judging whether or not theresult of calculation in said first calculating step is equal to orlarger than a reference value; and a first controlling step of makingthe data transmission rate request value decided in said deciding stepbe transmitted to the base station apparatus when it is judged in saidjudging step that the result of calculation in said first calculatingstep is equal to or larger than the reference value.
 6. A base stationapparatus used in a mobile communication system comprising a mobilestation apparatus that transmits data transmission rate request value,and the base station apparatus that selects the mobile station apparatusto which data is transmitted based on the data transmission rate requestvalue received from the mobile station apparatus and transmits data tothe selected mobile station apparatus at the data transmission raterequest value received from the selected mobile station apparatus,comprising: second receiving means for receiving the data transmissionrate request value transmitted from the mobile station apparatus;selecting means for selecting the mobile station apparatus to which datais transmitted based on the data transmission rate request valuereceived by said second receiving means; second calculating means forcalculating an average of a data transmission rate for transmitting datato the mobile station apparatus selected by said selecting means as theaverage data transmission rate; and second controlling means for makingthe average data transmission rate calculated by said second calculatingmeans be transmitted to the mobile station apparatus.
 7. A method ofcontrolling information transmission in a base station apparatus used ina mobile communication system comprising a mobile station apparatus thattransmits data transmission rate request value, and the base stationapparatus that selects the mobile station apparatus to which data istransmitted based on the data transmission rate request value receivedfrom the mobile station apparatus and transmits data to the selectedmobile station apparatus at the data transmission rate request valuereceived from the selected mobile station apparatus, comprising: asecond receiving step of receiving the data transmission rate requestvalue transmitted from the mobile station apparatus; a selecting step ofselecting the mobile station apparatus to which data is transmittedbased on the data transmission rate request value received in saidsecond receiving step; a second calculating step of calculating anaverage of a data transmission rate for transmitting data to the mobilestation apparatus selected in said selecting step as the average datatransmission rate; and a second controlling step of making the averagedata transmission rate calculated in said second calculating step betransmitted to the mobile station apparatus.
 8. A mobile communicationsystem comprising a mobile station apparatus that transmits datatransmission rate request value, and a base station apparatus thatselects the mobile station apparatus to which data is transmitted basedon the data transmission rate request value received from the mobilestation apparatus and transmits data to the selected mobile stationapparatus at the data transmission rate request value received from theselected mobile station apparatus, wherein the mobile station apparatuscomprises: first measuring means for measuring quality of the receivedsignal from the base station apparatus; deciding means for deciding thedata transmission rate request value based on the reception qualitymeasured by said first measuring means; first storing means for storingthe data transmission rate request value decided by said deciding means;first judging means for comparing the previous data transmission raterequest value stored in said first storing means and the latest datatransmission rate request value, and judging whether or not both thereofare different from each other; and controlling means for making thelatest data transmission rate request value be transmitted to the basestation apparatus when it is judged by said first judging means that theprevious data transmission rate request value and the latest datatransmission rate request value are different from each other, andwherein the base station apparatus comprises: second measuring means formeasuring quality of the received signal from the mobile stationapparatus; receiving means for receiving the data transmission raterequest value transmitted from the mobile station apparatus; secondstoring means for storing the data transmission rate request valuereceived by said receiving means by relating it to the mobile stationapparatus; second judging means for judging, when there is any mobilestation apparatus the data transmission rate request value of which hasnot been received this time by said receiving means, as for the relevantmobile station apparatus, whether or not the reception quality measuredby said second measuring means is equal to or larger than a referencevalue; and control means for using, when it is judged by said secondjudging means that the measured value of the reception quality is equalto or larger than the reference value, as for the relevant mobilestation apparatus, the previous data transmission rate request valuestored in said second storing means as the data transmission raterequest value to be used for selecting the mobile station apparatus towhich data is transmitted.
 9. A communication method in a mobilecommunication system comprising a mobile station apparatus thattransmits data transmission rate request value, and a base stationapparatus that selects the mobile station apparatus to which data istransmitted based on the data transmission rate request value receivedfrom the mobile station apparatus and transmits data to the selectedmobile station apparatus at the data transmission rate request valuereceived from the selected mobile station apparatus, comprising: a firstmeasuring step in which the mobile station apparatus measures quality ofthe received signal from the base station apparatus; a deciding step inwhich the mobile station apparatus decides the data transmission raterequest value based on the reception quality measured in said firstmeasuring step; a first judging step in which the mobile stationapparatus compares the previous data transmission rate request valuestored in first storing means for storing the data transmission raterequest value decided in said deciding step and the latest datatransmission rate request value, and judges whether or not both thereofare different from each other; a controlling step in which the mobilestation apparatus makes the latest data transmission rate request valuebe transmitted to the base station apparatus when it is judged in saidfirst judging step that the previous data transmission rate requestvalue and the latest data transmission rate request value are differentfrom each other; a second measuring step in which the base stationapparatus measures quality of the received signal from the mobilestation apparatus; a receiving step in which the base station apparatusreceives the data transmission rate request value transmitted from themobile station apparatus; a second judging step in which the basestation apparatus judges, when there is any mobile station apparatus thedata transmission rate request value of which has not been received thistime in said receiving step, as for the relevant mobile stationapparatus, whether or not the reception quality measured in said secondmeasuring step is equal to or larger than a reference value; and acontrol step in which the base station apparatus uses, when it is judgedin said second judging step that the measured value of the receptionquality is equal to or larger than the reference value, as for therelevant mobile station apparatus, the previous data transmission raterequest value stored in second storing means for storing the datatransmission rate request value received in said receiving step byrelating it to the mobile station apparatus as the data transmissionrate request value to be used for selecting the mobile station apparatusto which data is transmitted.
 10. A mobile station apparatus used in amobile communication system comprising the mobile station apparatus thattransmits data transmission rate request value, and a base stationapparatus that selects the mobile station apparatus to which data istransmitted based on the data transmission rate request value receivedfrom the mobile station apparatus and transmits data to the selectedmobile station apparatus at the data transmission rate request valuereceived from the selected mobile station apparatus, comprising: firstmeasuring means for measuring quality of the received signal from thebase station apparatus; deciding means for deciding the datatransmission rate request value based on the reception quality measuredby said first measuring means; first storing means for storing the datatransmission rate request value decided by said deciding means; firstjudging means for comparing the previous data transmission rate requestvalue stored in said first storing means and the latest datatransmission rate request value, and judging whether or not both thereofare different from each other; and controlling means for making thelatest data transmission rate request value be transmitted to the basestation apparatus when it is judged by said first judging means that theprevious data transmission rate request value and the latest datatransmission rate request value are different from each other.
 11. Themobile station apparatus according to claim 10, wherein said controllingmeans makes the latest data transmission rate request value betransmitted periodically to the base station apparatus when it is judgedby said first judging means that the previous data transmission raterequest value and the latest data transmission rate request value arethe same.
 12. A method of controlling information transmission in amobile station apparatus used in a mobile communication systemcomprising the mobile station apparatus that transmits data transmissionrate request value, and a base station apparatus that selects the mobilestation apparatus to which data is transmitted based on the datatransmission rate request value received from the mobile stationapparatus and transmits data to the selected mobile station apparatus atthe data transmission rate request value received from the selectedmobile station apparatus, comprising: a first measuring step ofmeasuring quality of the received signal from the base stationapparatus; a deciding step of deciding the data transmission raterequest value based on the reception quality measured in said firstmeasuring step; a first judging step of comparing the previous datatransmission rate request value stored in first storing means forstoring the data transmission rate request value decided in saiddeciding step and the latest data transmission rate request value, andjudging whether or not both thereof are different from each other; and acontrolling step of making the latest data transmission rate requestvalue be transmitted to the base station apparatus when it is judged insaid first judging step that the previous data transmission rate requestvalue and the latest data transmission rate request value are differentfrom each other.
 13. A base station used in a mobile communicationsystem comprising a mobile station apparatus that transmits datatransmission rate request value, and the base station apparatus thatselects the mobile station apparatus to which data is transmitted basedon the data transmission rate request value received from the mobilestation apparatus and transmits data to the selected mobile stationapparatus at the data transmission rate request value received from theselected mobile station apparatus, comprising: second measuring meansfor measuring quality of the received signal from the mobile stationapparatus; receiving means for receiving the data transmission raterequest value transmitted from the mobile station apparatus; secondstoring means for storing the data transmission rate request valuereceived by said receiving means by relating it to the mobile stationapparatus; second judging means for judging, when there is any mobilestation apparatus the data transmission rate request value of which hasnot been received this time by said receiving means, as for the relevantmobile station apparatus, whether or not the reception quality measuredby said second measuring means is equal to or larger than a referencevalue; and control means for using, when it is judged by said secondjudging means that the measured value of the reception quality is equalto or larger than the reference value, as for the relevant mobilestation apparatus, the previous data transmission rate request valuestored in said second storing means as the data transmission raterequest value to be used for selecting the mobile station apparatus towhich data is transmitted.
 14. The base station apparatus according toclaim 13, wherein the reception quality measured by said secondmeasuring means is an SIR of a predetermined pilot symbol signal.
 15. Amethod of controlling information transmission in a base stationapparatus used in a mobile communication system comprising a mobilestation apparatus that transmits data transmission rate request value,and the base station apparatus that selects the mobile station apparatusto which data is transmitted based on the data transmission rate requestvalue received from the mobile station apparatus and transmits data tothe selected mobile station apparatus at the data transmission raterequest value received from the selected mobile station apparatus,comprising: a second measuring step of measuring quality of the receivedsignal from the mobile station apparatus; a receiving step of receivingthe data transmission rate request value transmitted from the mobilestation apparatus; a second judging step of judging, when there is anymobile station apparatus the data transmission rate request value ofwhich has not been received this time in said receiving step, as for therelevant mobile station apparatus, whether or not the reception qualitymeasured in said second measuring step is equal to or lager than areference value; and a control step of using, when it is judged in saidsecond judging step that the measured value of the reception quality isequal to or larger than the reference value, as for the relevant mobilestation apparatus, the previous data transmission rate request valuestored in second storing means for storing the data transmission raterequest value received in said receiving step by relating it to themobile station apparatus as the data transmission rate request value tobe used for selecting the mobile station apparatus to which data istransmitted.